Gaseous illuminating device



July 9, 1935.

c. H. BRAsELToN GASEOUS ILLUMINATING DEVICE Filed May 17, 1932 5 Sheets-Sheet l INVENTOR 3v4 Sheets-Sheet 2 Filed May 17, 1932 INVENTOR July 9, 1935 c. H. BRAsELToN GASEOUS ILLUMINATING DEVICE Filed May 17, 1932 5 Sheets-Sheet 5 INVENTOR Cil Patented July 9, 1935 UNITED STATES GASEOUS ILLUMINATING DEVICE Chester H. Braselton, New York, N. Y., assignor to Sirian Lamp Company, Newark, N. J., a corporation of Delaware Application May 17, 1932, Serial No. 611,815

7 Claims.

This invention relates to illuminating devices and particularly to such devices in which a gaseous discharge is produced. In my application entitled Electrical discharge device led June 3, 1930, Serial No. 459,048, a discharge device is disclosed in which an electron emitting element is energized in the presence of an ionizable gas under certain conditions of pressure and voltage drop along theelement. Thisproduces a halo of ionization with an intense illumination in the vicinity of the filament, following the lament from end to end, and apparently caused by the emissivity of the filament and the potential drop along the element. In Operating the device on a volt circuit and with the element mounted in a single unit similar to an ordinary electric light bulb so that it could be used in an ordinary electric light bulb socket it was found that in some instances there was a tendency to produce an arc between the high potential points of the circuit which when once started caused destruction of the lament and rendered the device useless.

It is an object of the present invention to provide a discharge device in which the tendency to arc across the high potential points is prevented.

Another object of the invention is to provide an auxiliary controlling means for the discharge.

Another object of the invention is to provide a discharge lamp with a pair of tubular transparent members therein in which the discharge occurs.

Other objects of the invention and objects relating particularly to the method of constructing and assembling the various parts will be apparent as the description thereof proceeds.

Several embodiments of the invention have been illustrated in the accompanying drawings in which:

Fig. 1 is a sectional front elevational view of one form of the device;

Fig. 2 is an end elevational view of theelements shown in Fig. 1;

Fig. 3 is a sectional plan view of the elements of Fig. 1 taken on the line 3-3 of that figure;

Figs. 4 and 5 are enlarged sectional elevational views of the electron emitting element of Fig. 1;

Fig. 6 is a sectional front elevational view of another embodiment of the device;

Fig. 7 is a sectional plan view taken on the line 1--1 of Fig. 6;

Fig. 8 is a sectional front elevational view of another modified form of the invention;

Fig. 9 is a sectional front elevational view of another modified form of the invention;

Fig. 10 is a sectional front elevational View of still another modified form of the invention;

Fig. 11 is a sectional plan view of the elements 5 of Fig. 10 taken on the line II--II of that gure; and y Fig. 12 is an enlarged sectional side elevational view of a portion of the supporting means for the elements of Fig. 10 taken on the line I2-I2 10 of that figure.

Referring now more specically to the drawings, one embodiment of the invention is shown in Fig. l as comprising an envelope I0 with which a press II is formed integral in a manner well 15 known in the art for supporting the elements. A pair of conducting support rods I2 and I3 are sealed in the press and have wires I4 and I5 respectively attached to them for connecting the device in a circuit.

A flat member `Iii made of some insulating material such as quartz, isolantite, crolite,for the like, is formed in the shape of a figure 8 and is provided on its upper surface with a pair of grooves I1 and I8 which are circular and sub- 25 stantially tangent to each other at the center of the member. At the centers of the circles formed by the grooves I1 and I8 I provide holes I9 and 20 respectively through which the support rods I2 and I3 are adapted to t. The upper 30 ends of the support rods I2 and I3 are vbent outwardly and then upwardly and inwardly again so that they form a means to rigidly hold the member I6 upon the top of the press Il which is formed at for that purpose and may if de` 35 sired be extended somewhat so as to form a more steady foundation for the member. A support rod 2| is provided at the center ofthe member IBand is preferably anchored therein bymeans of an enlarged head 22 which may be provided on the rod and which lies in a recess provided for that purpose in the bottom of the member. The rod 2| is preferably molded into the member so that it is rigidly connected thereto and extends upwardly at right angles to the plane` of 45 the member for a distance of about two-thirds of the height of the bulb.

A pair of transparent tubes 23 and Y24 open at both ends are mounted parallel to each other and upon the member I6, the tube 23 fitting into 50 the groove l1, while the tube 24 ts into the groove I8. A suitable cement 25, such as crolite cement, may be provided in each of the grooves to act as a seal for the bottom of the tube and to aid in holding the tubes in position upon the member I6. At the top of the tubes I provide a clip 26 having depending lugs 21 and 28 which fit respectively into the tops of the tubes 23 and 24 and hold the tubes together and against the center rod 2I to which the clip 26 may be welded. Thus the tubes 23-and 24 are rigidly supported upon the member I6.

The tubes 23 and 24 may be formed` of any transparent material which is capable of standing a high temperature such as quartz or pyrex glass, or uviol glass and may be made very thin, their only function being to act as an auxiliary control for the discharge.

A pair of electron emitting elements 29 and 30 have their lower ends attached respectively to the support rods I2 and I3, while their upper ends may be connected to a cross member 3| which is in turn welded to the upper end of the clip 26. Thus the electron emitting elements are rigidly supported within the tubes.

The electron emitting elements 29 and 30 may be formed similarly to'those described in the application above referred to. I preferably use a closely wound coil 32 of a resistance wire such as tungsten, molybdenum, tantalum, and the like, and coat the entire coil with an electron emitting materialw33 such as one or more of the oxides of the alkaline earth metals with a suitable binder which is burned off -in the exhausting or treating process before the lamp is finished. Any of the well known oxides may be used for this purpose, such as barium and strontium oxides or mixtures of such oxides, and I may prefer to include an oxide, such as calcium oxide, having selective radiation. In some instances I maydesire to protect the ends of the elements where they are attached to the support rod by means of an additional coil 34 of one or two .turns of a refractory metal wire, such as 401 tungsten\ around the end of the electron emituit ting element but spaced therefrom and attached to the support rod adjacent to the point where the element is attached. This additional coil of wire receives a portion of the discharge which might normally tend to be received by the extreme end of the element with the result that the end is protected from disintegration due to this bombardment.

Other types of electron emitting elements might be used such as the construction of Fig. 5 where the wire coil 35 has each turn individually coated with electron emitting material 36, or the coil of wire may be filled with a core of electron emitting material, or the material may be incorporated in the wire itself, such as the well known thoriated tungsten wire which may be prepared by treating tungstic acid and barium nitrate.

In assembling such a lamp the press provided with its two support rods I2 and I3 and associated leading-in wires I4 and I5 is first made and then the member I6 is placed upon the atop thereof by slipping the support rods I2 and I3 through the holes I9 and 20 in the member. The rods are then bent outwardly and then upwardly to secure the member in position on the top of the press. The holes I9 and 20 and the grooves I1 and I8 are then filled with a suitable sealing cement, and the electron emitting' elements are welded to the ends of the support rods. The tubes 23 and 24 are then placed over the elements and are seated in their respective grooves. The clip 26 with the cross member 3I attached is placed on top of the transparent tubes and Welded to the central support rod 2| and the upper ends of the electron emitting elements may then be welded to the cross member 3|.

With the parts thus assembled the bulb may be connected to a vacuum pump and an oven placed over it to raise the temperature to between 350 and 400 C or to as high a temperature as the glass will stand without softening. Current may at the same time be run through the elements to raise the temperature thereof to about 600 C. This heat is continued until a high vacuum of approximately .5 micron is obtained and all the gases have been removed from the envelope which is evident by no fluorescence when high tension current from an induction coil is directed against the walls of the bulb. Current may then be increased through the filaments and the temperature thereof slowly raised until they are a bright red when the temperature will be about 800 C. This drives out any binder in the electron emitting material and certain occluded gases which have not yet been removed. The pump continues to remove from the envelope any gases which are driven out of the elements or other parts.

When no more gas is found in the envelope the oven may be raised and the elements heated to slightly less than 1200" C. to drive out any other occluded gases or vapors which may be present. The pump may then be shut off and a slight amount of an inert gas, such as neon, at a pressure of about 1/2 mm. may be admitted in the envelope and the filament current turned on again. This causes reddish spots of discharge to occur on the filaments or other parts of the lamp which gradually increase in size until a diffused glow appears inside of the bulb substantially filling it, and the action tends to activate the electron emitting coating to raise the electron emitting efficiency thereof. This process should take about ten minutes but if white spots appear it is an indication of other gases being present and the envelope should be exhausted again and the process repeated.

When the activation is completed the pump may again be connected to the envelope and the gas pumped out until a high vacuum is again produced. The filament circuit may-then be disconnected and the pump turned off and an inert gas may be admitted into the bulb at a pressure in the neighborhood of 200 mm. of mercury. The inert gas may preferably be one or more of the monotomic gases such as neon, argon, helium, krypton, or xenon, and metal vapors, such asthe vapors of mercury, rubidium, csium, and sodium, may also be added, if desired, to increase the conductivity or to produce color effects. For purposes of illumination I may prefer to use a mixture of neon and argon gas in the proportion of about 50 mm. of neon and 150 mm. of argon. These gases should preferably be chemically pure or at least should not have an excess of 1% of impurities. y

When a lamp so constructed is connected in a circuit and the elements 29 and 30 energized a discharge occurs through the gas in the vicinity of the elements and surrounding them like a halo apparently passing from end to end thereof. This effect is produced even without the transparent tubes 23 and 24 but with the tubes present the discharge may be made to not only surround the elements but to spill over the top of the tubes from one tube to the other forming a cascade of a gaseous illumination from one tube into the other.

In Fig. 6 a modified form of the invention is shown in which a bulb 31 is provided with a press 38 in which a pair of support rods 39 and 48 are sealed. These support rods are used not only for supporting the electron emitting elements but also for supporting the transparent tubes 4I and 42, as the latter are fusedto the support rods just below the upper ends thereof as indicated respectively at 43 and 44. A central support rod 45 which is sealed in the press 38 is provided with a cross member 46 at the top thereof for supporting the upper ends of the two elements 41 and 48, the lower ends of which are connected to the support rods -39 and 48 respectively. These elements 41 and 48 may be the same type as already described in connection with the preceding figures. With this construction the lower ends of the support rods 39 and 48 between the tubes and the press 38 are provided with insulated coatings 49 and 58 which may be any suitable insulating material capable of standing relatively high temperatures and of adhering to the support rods. Such a material is described in the application of Samuel Ruben, Serial No. 499.845. led December 3, 1930.

In Fig. 8 is shown another modication of thc invention in which the envelope is provided with the usual press 52 in which is sealed a pair of support rods 53 and 54, and a central support rod 55 which extends upwardly to a point adjacent the top of the bulb. A pair of transparent tubes 56 and 51 are provided with tapered lower ends 58 and 59 which go down to a diameter slightly larger than the support rods. The press 52 may be provided with indentations or recesses 68 and 6I surrounding the support rods 53 and 54 respectively to receive the restricted ends 58 and 59 of the tubes 56 and 51. These ends fit down into the recesses and the latter are provided with a small amount of insulating cement 62 to seal the lower ends of the tubes. A pair of electron emitting elements 63 and 64, similar to those already described, may be attached to the support rods 53 and 54 at their lower ends and to the cross member 65 at their upper ends, this cross member being welded to the upper end of the support rod 55. A suitable clip 66 is provided which may be welded to thev upper end of the suppart rod 55 and has downwardly extending portions 61 and 68 to go down into the tubes 56 and 51 respectively and a central lug 66a to space the tubes apart. This holds the upper ends of the tubes in fixed position with respect to the support rods in-a similar manner to the clip 26 in Fig. l. Leading-in wires 69 and 18 may be attached respectively to the support rods 53 and 54 for making the connection to the lamp.

In some instances it may be found desirable to form the transparent tubes integral with the press and. if so the construction of Fig. 9 may be used where the envelope 1| is provided with a press 12 with which a pair of upstanding tubes 13 and 14 are formed integral. The lower ends of the tubes are preferably reduced in diameter on the side away from the axis of the lamp as at 15 and 16 so that the press need not be made too large in diameter at this point. Support rods 11 and 18 are sealed in the press and the upper ends thereof extend respectively into the tubes 13 and 14 and leading-in wires 19'and 88 are' attached to these support rods. The electron emitting elements 8| and 82 are similar to those already described having their lower ends attached to the support rods 11 and 18 while the upper ends of the elements are attached to a cross connecting member 83 which is welded to a clip 84 mounted on the top of the tubes. The clip 84 has a central depending member 85 which goes between the two tubes and a pair of spaced depending members 86 and 81 to extend down into the tubes 13 and 14 respectively. With this construction it is necessary to weld the lower ends of the electron emitting elements upon the support rods by having a welding tool which extends into the open end of the tube. o1' the elements may be attached to the support rods by a suitable conductive paste such as one made of powdered tungsten, powdered carbon. or the like.

In assembling this device it is obvious that after the two electron emitting elements are attached to the support rods the tubes may be slipped over them the restricted ends being set down into the recess in the press provided to receive them and then the upper ends of the electron emit-ting element may be attached to the cross member which may be already attached to the support rod and the clip secured in place. This construction therefore, lends itself to very easy assembly.

In Fig. another construction is shown in which the transparent tubes are supported upon a central stem of glass. In this construction the bulb 88 is provided with the press 89 which has a pair of support rods 98 and 9| sealed therein connected to the leading-in wires 92 and 93 respectively. A central glass rod 94 is fused to the press and extends vertically along the axis of the bulb to a point near the top. The rod is provided a short distance from the press with a support Wire 95 fused therein, and adjacent the top another wire 96 is sealed in the rod, and a bead 91 may be provided at the top through which a cross member 98 extends substantially at right angles to the other support wires. A pair of brackets 99 and |88 may be made of pressed sheet metal and comprise a pair of circular bands |8| and |82 joined together at the center with a flat portion |83 which may be cut out at |84 to receive the central rod 94. The bracket 99 may be welded to the wire 95 at the bottom and the bracket |88 at the top may be welded to the wire 96 as indicated. A pair of tubes |85 and |95 may be then mounted respectiveiy in the ring members |8| and |82, the positioning of the tubes in the brackets being done before the brackets are attached to the central support posts 94. The tubes |85 and |86 may have sealed in their lower ends short support rods |81 and |88 respectively to which the lower ends of the electron emitting elements |89 and |8 may be welded. These support rods |81 and |08 may be in turn welded to the support rods 98 and 9| which anchor the electron emitting element as Well as the tubes |85 and |86 from vertical movement. The upper ends of the electron emitting elements |89 and H8 may be welded to the cross member 98 thus supporting the whole structure and connecting the electron emitting elements in series.

Many other embodiments of the invention and variations thereof, such as combinations of the various structures shown, may be resorted to without departing from the spirit of the invention and I do not, therefore., desire to limit myself to what has been shown and described except as such limitations occur in the appended claims.

What I desire to secure and claim by Letters Patent is: l

1. In a device of the class described an envelope, a press formed integral with said envelope, an insulating member mounted upon the top of said press, a pair of support rods sealed in said press, means to hold said insulating member upon said press with the support rods extending therethrough, an electron emitting element attached to each of said support rods, a transparent tube surrounding each of said electron emitting elements and support rods and resting upon said insulating member, means to seal the lower ends of said transparent tubes. means to electrically connect the upper ends of said electron emitting elements, and means to hold in spaced relation the upper ends of said tubes and to secure said tubes upon said insulating member.

2. In a device of the class described an envelope, a press formed integral with said envelope,

a pair of support rods sealed in said press, a pairv of electron emitting elements one attached to each of said support rods, a pair of transparent tubes one surrounding each of said electron emitting elements and fused at the lower ends to said support rods, said tubes being open at their upper ends, a central support rod sealed in said press and extending up between said tubes and slightly above the tops of them, and a connector supported upon said rod and holding the upper ends of said element.

3. In a device of the class described an envelope, a press within said envelope, a pair of support rods mounted on said press, a pair of electron emitting elements one attached to each of said support rods, a pair of transparent tubes one surrounding each of said electron emitting elements and fused at the lower ends to said support rods, the upper ends of said tubes being open, a central support rod sealed in said press and extending upwardly between said tubes terminating at a point above the top of them, a connector attached to the upper end of said support "rod and connected to the upper ends of said elements, and an ionizable gas within said envelope.

4. In a device of the class described, an envelope, a press within said envelope, a pair of support rods sealed in said press, a circular depression at the top of said press surrounding each of said support rods, an electron emitting element attached to each of said support rods, a tubular member surrounding each of said electron emitting elements, said tubular member having a neck at its lower end adapted to iit into said depression, means to seal the neck in said depression against electrical conduction through the joint therebetween, a icentral support rod sealed in said press and extending upwardly between said tubes and terminating above the tops of them, a connector attached to the upper end of said rod and to the upper ends of said elements. and means to secure the upper ends of said tubes in spaced relation and to hold said tubes against vertical movement within said bulb.

5. Ina device of the class described an envelope, a press within said envelope and integral therewith, a pair o! support rods sealed in said press, a depression in the top of said press and surrounding each of said support rods, an electron emitting element attached to each of said support rods, a transparent tubular member surrounding each of said electron emitting elements, a neck on thellower end of each of said tubular members and adapted to ilt into said depression, means to seal said neck in said depression against electrical discharge through the joint therebetween, a central support rod sealed in said press and extending upwardly between said tubes and terminating above the top of them, a connecting rod attached to the top of said support rod and supporting the upper ends of said elements, means to secure said tubular members in spaced relation and to hold them against vertical movement within said bulb, and an ionizable gas within said bulb.

'6. In a device of the class described an envelope, a press within said envelope, a pair of transparent tubular members fused to the top of said press and extending upwardly and in parallel relation, a support rod sealed through said press in each of said tubular members, an electron emitting element attached to each o1' said support rods and extending upwardly through said tubular members, and means to support the upper ends of said electron emitting elements from the top of said tubular members.

'7. In a device of the class described an envelope, a press within said envelope, a central supporting rod fused to said press, a pair of brackets mounted in spaced relation along said supporting rod, a pair of parallel tubular members secured in( said brackets, a pair of connecting rods fused into the lower ends of said tubular members, a pair of support rods fused in said press and welded to said connecting rods, a connector mounted on the top of said central support rod, the upper end of said elements being welded to said connector, and an ionizable gas within said envelope.

CHESTER H. BRASELTON. 

